Method for making unwoven fabrics



United States Patent Piero Modigliani, Plandome, N. Y., assignor to Johns- Manville Corporation, New York, N. Y., a corporation of New York 'No Drawing. Application April 8, 1954, Serial No. 421,960

7 Claims. (Cl. 154-90 The present invention relates to improved methods of making unwoven fabrics and tapes of glass filaments, particularly fabrics of the type disclosed in Modigliani Patent No. 2,609,320. a t a In the above patent, there is disclosed a method includ ing the steps of forming a condensed mat ofa plurality of layers of filaments with the filaments extending generallytransversely of the mat and with the filaments of adjacent layers crossing at acute anglesg and expanding the matin a direction transversely of the "general lay of the filaments to form an elongated web. The condensed mat in this general method is formed by drawing glass filaments directly from a melting furnace by a rotating drum to accumulate the filaments on the peripheral surface thereof. The furnace and drum are relatively reciprocated so that the filaments are accumulated in a plurality of layers, the filaments of which extend in crossed relation to the filaments of adjacent layers, the angle of crossing depending upon the relative speeds of rotation and reciprocation. In normal practice the furnace is reciprocated at a rate of about 14 feet per minute and the drum is rotated at the rate of about 2,400 feet per minute, and consequently the angle between filaments of adjacent layers is quite acute. This action is continued until a mat of desired thickness is built up. Where the condensed mat is composed of layers of tapes or strands, as in my copending application, Serial No. 401,006, filed December 29, 1953, the strands or tapes may be peeled from the drum and rewound on spools. Where it is desired to form products of the type shown in the above patent, the mat is removed from the drum by slitting it longitudinally of the drum, and is then expanded or stretched in a direction substantially perpendicular to the original lay of the filaments, the expansion being similar to the expansion of a lazy tongs. In expanding a condensed mat, the mat is merely grasped at one of its edges extending in the direction of the filaments and is continuously pulled from this edge either by hand or by a moving conveyor. Depending upon the exact manner of expansion and the degree of expansion, a relatively open elongated web constituting an unwoven fabric of varying fiber orientation is formed. It has been customary to apply binders to the filaments during formation of the condensed mat and/or prior to, during or after expansion, the binder subsequently being cured or set to bind the filaments of the web together. In general, the method of the present invention differs from the prior method in that it includes the step of applying to the filaments during accumulation on the drum a solution containing a complex compound having functional groups which react with or firmly bond to the surface of the filaments and other functional groups which may be reacted with or bonded to a resin to be employed as a binder. This general type of compound may be applied to the filaments in solution with water or other solvent and an agent for accelerating the bonding process.

There are a number of advantages in applying to fila- 2,729,582 Patented Jan. 3, 1956 ments as they are accumulated on the drum solutions containing compounds of the type described. One of these advantages is that the material is applied at a time when the filaments have just been formed and hence are clean. Also, because of the fact that the drum is rotating rapidly, the vaporizable portions of the solution are quickly evaporated, leaving only the dry solid material on the filaments without necessitating a separate drying step. These advantages accrue regardless of any further use of the mat. Moreover, where the condensed mat is to be expanded, application of such a material prior to expansion unexpectedly enables the condensed mat to be expanded more uniformly to provide a greater length of elongated web as well as a higher quality product.

The invention will be more fully understood from the following example. During accumulation of a condensed mat on a drum, a solution consisting of parts of methacrylato chromic chloride diluted with 4,680 parts of watenhaving added thereto 222 parts of aqueous ammonia is sprayed periodically on the filaments. In spraying the solution, the mat being formed on the drum is completely wetted at about 10 to 15 minute intervals. By reason of the speed of the drum, only a small amount of solids by weight of the mat can be retained on the filaments, and where a speed in the neighborhood of 2,400 feet per minute is employed, about 0.15 to 1.0% solids are retained. After accumulation of a mat of the desired thickness, the mat is removed from the drum in either of the forms described above and the filaments of the condensed mat apparently are coated with dry, solid methacrylato chromic chloride which is firmly bonded to the surface of the glass filaments. Where the mat is expanded into a fabric, the ease and uniformity of expansion is noticeably better than in prior practice. In the latter stages of expansion the web is dipped in a bath of polyester resin and then passed through an oven to cure the resin. The resin is apparently reacted with the methacrylato chromic chloride since it becomes firmly adhered to the filaments. The fabric thus produced has been found particularly adapted for use in making so-called plastic laminates.

It will be apparent from the above example that the basic method of the present invention lies in applying to the filaments of a condensed mat during formation on a drum a compound which strongly adheres to the glass and to a binder or resin subsequently to be applied. The fiber thus accumulated may be expanded to form an elongated web, or may be arranged in strand or tape form. When fiber is arranged in the desired form, the product is finished by applying the binder and setting it. Other materials than the methacrylato chromic chloride specified above will accomplish similar results when applied to glass filaments in accordance with the present method. Any material which will strongly adhere to glass and when dry has a non-tacky surface apparently will accomplish the desired results of improving the expansion of the mat. Some of the materials which may be so used obviously also have special advantages of modifying the surfaces of the glass filaments so that they will strongly adhere to particular types of resins. In the present method such resins, or other binder, may be applied to the mat at any time after removal of the fiber from the drum, but for expansion purposes best results are obtained when the binder is applied after expansion (at least to some extent) of the mat.

Vinyltrichlorosilane in a 3.5% solution with xylol will accomplish substantially the same results in the method of the present invention as methacrylato chromic chloride. A compound which produces results similar to the results produced by vinyltrichlorosilane but differs therefrom by having been modified to eliminate the chlorine, and which constitutes a neutral hydrocarbon-soluble silicone polysavanna rnextjs marketed gas ZLinde-lsize GS1. This silicone p y as Well other m la lsilican rnql mers,ha been found useful in the present method, particularly where phenolic, polyester and epoxy laminates are to be formed Q MiO L -Y qt erzsilanesghaviugpropertiestsimilar 1. th yinyltril hl roailane :m y "he tused.

Having thus described any ;;inyenti,on in mather ::-full detail, it willhe understood ;thatythesel:details need 2110!. be. strictly adhered ;to but,,that :various :changes;v and modificationsmayssuggestgh Instill/@5310iolle'qsklllfiddnIthfiaft, alLfalling within;the;;scope ofthetinvention. as defined byzthesnbiqined slairns- 1. A n tethod f jormingan :unwoyen, fabric: comprising drawing glass ments tfrom orifices of afurnace-:with g fll l tfor g: a :Qondensedsmat:;bytwinding a :plurality of layerspfisaid:filamentslon'saidtdrumzwithtthe filaments of adjacent layersserossinglat acute-angles, applyingto the filamentstdnringtwindingacomplex-compound having a fiunctienal group which :honds to the ,surfacesfiof the filaments .:an d-;a;functignaltgroup:whichzbonds to a abin'der subsequently JO herapplierd, :removing said .mat from-:.,the dmmiapplyillglsflid ,indergintunset.'formttogthe'filaments at, anytime after removahohthetmatfrom the drum,= and settingthetbinder. 1

.12- Atmelhoidtflfiforrningtanumwoyen fabric; comprising iorming a cpndensedrzmat Jay: windingta iP1urality.:oflayers 9 afilamsu ann a ,:d;1:1lm;:.wi,th.-,-;thetfilarnents of adjacent layersl cross' at acute; angles,w applying stonthe tfilaments durin tw ndiagzafiomplex;compoundzhavinga functional I expanding itjn a;d i,re,ction transversely of. thetgeneral lay 4 removal of the mat from the drum, and setting the binder v.atternonatzleticul.oiezapansionnfsth :mat

3. A method of formingtan unwoven fabric comprising forming a condensed mat of a plurality of layers of filaments with the filaments extending generally trans versely of the mat and with filaments of adjacent layers crossing at acute angles said mat having applied thereto a c mp e v c mpou d hav ng-a .-=fun, i .nal gr up whi h bonds to the surfaces of'the filaments and a functional group which bonds to a bindensubsequcntly:tolbcrapplied, expandingthe ;mati-lIL a-direction-Ztnansversely ofthe general lay of the filaments to form an elongated Web,-applyn 's b d r in lunse fifiq mtt thett lam t at y time after 'formationof thecondensed mat, and setting the binder after completion of expansion of the mat.

4. The method'of-claim 3twherein-said complex compound is methacrylato chromic chloride.

5. The method of claim 3 wherein said complex com- P0 lnd isvinyltrichlorosilane.

l6. The method of-aclaim 3 swherein thecomplex comp und ;is iajneutral hydrocarbon solublesilicone polymer.

7. A method comprising drawing glass filaments from orifices of a furnace .with a. drum, 1 forming a condensed mat by windinga l'pluralityrof layers-of-said filaments on said drum with therrfilaments of; adjacent layers; crossing at acute;angles, and applyingtozther filaments during winding a -,complex compound; having a functional group which bonds to':the.-.surfaces 0f thew-filaments and a functional iollpawhichtbondstto a-:bin den subsequently tobe applied tothe filaments. 7

References Cited inthefile, of .thispatent UNITED STATES PATENTS .M diglia i -t-r. aSept.- ,95 

1. A METHOD OF FORMING AN UNWOVEN FABRIC COMPRISING DRAWING GLASS FILAMENTS FROM ORIFICES OF A FURNACE WITH A DRUM, FORMING A CONDENSED MAT BY WINDING A PLURALITY OF LAYERS OF SAID FILAMENTS ON SAID DRUM WITH THE FILAMENTS OF ADJACENT LAYERS CROSSING AT ACUTE ANGLES, APPLYING TO THE FILAMENTS DURING WINDING A COMPLEX COMPOUND HAVING A FUNCTIONAL GROUP WHICH BONDS TO THE SURFACES OF THE FILAMENTS AND A FUNCTIONAL GROUP WHICH BONDS TO A BINDER SUBSEQUENTLY TO BE APPLIED, REMOVING SAID MAT FROM THE DRUM, APPLYING SAID BINDER IN UNSET FORM TO THE FILAMENTS AT ANY TIME AFTER REMOVAL OF THE MAT FROM THE DRUM, AND SETTING THE BINDER. 